Surgery for Wilms tumour

Most children with Wilms tumour will have surgery. The type of surgery used depends mainly on whether or not the tumour is resectable, which means that it can be removed with surgery. It also depends on whether or not there are tumours in both kidneys. When planning surgery, the healthcare team will also consider other factors, such as the child’s overall health, if the child has 1 or 2 kidneys and how well the kidneys are working.

Surgery may be done for different reasons. Your child may have surgery to:

completely remove the tumour

diagnose, stage and assess the extent of disease

The following are the types of surgery most commonly used to treat Wilms tumour. The child may also have other treatments before or after surgery.

Before surgery

Before surgery, doctors will use diagnostic tests to find out the extent of the tumour. This usually includes imaging tests such as computed tomography (CT) scan and magnetic resonance imaging (MRI). Ultrasound is also commonly used. If imaging tests suggest that there might be cancer in the other kidney, doctors will try to decide whether or not the tumours can be removed with surgery.

Tumours that can be removed with surgery are called resectable. Those that can’t be removed with surgery are called unresectable. Tumours may be considered unresectable when:

there are tumours in both kidneys

the child has only one kidney

the tumour is very large and has grown beyond the midline, which is the line that divides the body in right and left halves

the tumour has grown deep into the veins of the liver or heart

the tumour has spread to nearby vital structures or organs and these would also have to be removed

surgery to remove the entire tumour would cause significant or unnecessary damage

the cancer has spread to the lungs and they are not working properly

Even when a tumour is thought to be unresectable, the surgeon will examine it during surgery to determine if it can actually be removed. The surgeon will also take a sample for biopsy. Chemotherapy, with or without abdominal radiation therapy, is given to treat unresectable tumours. After chemotherapy is finished, the surgeon will do a second-look surgery to reassess and remove the tumour, if possible.

Radical nephrectomy

The most common surgery for Wilms tumour is a radical nephrectomy. A radical nephrectomy removes the entire kidney, including the adrenal gland, the ureter and the surrounding fat. With large tumours, the surgeon may also remove the renal vein and parts of the large vein in the abdomen (called the inferior vena cava).

Partial nephrectomy

Partial nephrectomy is also called nephron-sparing surgery. It removes the tumour along with a margin of healthy tissue around it. Partial nephrectomy is only used in certain circumstances as there is a slightly higher chance of recurrence of the tumour. It is typically only used when:

there are tumours in both kidneys at diagnosis

the child has only one kidney

the other kidney is not working well

Assessing the extent of disease

Knowing if Wilms tumour has spread to the lymph nodes, the other kidney or nearby organs helps the healthcare team determine the stage and further treatment.

During surgery, the surgeon usually makes a surgical cut, or incision, in the abdomen and checks the entire abdominal area. This includes close examination of the peritoneum, which is the membrane that lines the walls of the abdomen and pelvis and covers most of the abdominal organs. The surgeon will also feel the renal vein and inferior vena cava, which is a large vein that receives blood from lower limbs and organs of the pelvis and abdomen and empties into the right atrium of the heart. The surgeon also examines nearby organs such as the liver. A sample, or biopsy, may be taken from any suspicious areas.

During the operation to remove the tumour, the surgeon will also remove lymph nodes near the kidney. Surgery to remove the lymph nodes is called lymph node dissection. If possible, only a few lymph nodes are removed (called lymph node sampling). Sometimes just a biopsy is done on some of the lymph nodes. Samples from the lymph nodes are examined under a microscope to determine the stage of the cancer. This is very important to do as sometimes cancer may have spread to the lymph nodes without enlarging them.

Biopsy

In most cases of Wilms tumour, it is best to remove the primary tumour without doing a biopsy first. But during surgery, the surgeon may find that the tumour can’t be completely removed with surgery, or it is unresectable. A tumour may be unresectable if it is large and has grown into surrounding tissues and vital structures. If the tumour is unresectable, then the surgeon may take a sample of the kidney for a biopsy.

A biopsy will also be done if the child only has one kidney. If both kidneys contain cancer by imaging at diagnosis, a biopsy or nephrectomy is usually delayed until after 6 weeks of chemotherapy.

Surgery for metastases

Surgery may be used to remove cancer that has spread, or metastasized, to the liver or lungs or to biopsy an area on the lungs if it showed a spot on imaging. Chemotherapy and radiation therapy are usually given before surgery. If tumours remain in the liver or lung after these treatments, surgery may be done again to remove them.